boost::optional -> std::optional

Author: artemp

src/mapnik_image.cpp

@@ -173,7 +173,7 @@ mapnik::image_dtype get_type(mapnik::image_any & im)
 
 std::shared_ptr<image_any> open_from_file(std::string const& filename)
 {
-    boost::optional<std::string> type = type_from_filename(filename);
+    auto type = type_from_filename(filename);
     if (type)
     {
         std::unique_ptr<image_reader> reader(get_image_reader(filename,*type));

src/mapnik_layer.cpp

@@ -25,7 +25,6 @@
 #include <mapnik/layer.hpp>
 #include <mapnik/datasource.hpp>
 #include <mapnik/datasource_cache.hpp>
-#include "python_optional.hpp"
 //pybind11
 #include <pybind11/pybind11.h>
 #include <pybind11/operators.h>

src/mapnik_rule.cpp

@@ -25,7 +25,6 @@
 #include <mapnik/rule.hpp>
 #include <mapnik/expression.hpp>
 #include <mapnik/expression_string.hpp>
-//#include "python_variant.hpp"
 //pybind11
 #include <pybind11/pybind11.h>
 #include <pybind11/operators.h>